Systems and methods for spray drying in microfluidic and other systems

The present invention generally relates to microfluidics, and to spray drying and other drying techniques. By at least partially drying fluids within a microfluidic channel, instead of or in addition to conventional spray drying techniques, better control of the drying process can be achieved in certain aspects of the invention. In addition, various embodiments of the invention are generally directed to systems and methods for drying fluids contained within a channel such as a microfluidic channel. For example, a fluid may be partially or completely dried within a microfluidic channel, prior to being sprayed into a collection region. In some embodiments, gases such as air may be directed into a channel containing a fluid, which may facilitate drying of the fluid. In some cases, the fluid may be accelerated due to the introduction of gases into the channel, and in certain embodiments, droplets of fluid may be disrupted to form smaller droplets as a result. In certain cases, the fluids may also be dried to form supersaturated droplets

Commercial Value and Challenges of Drop-Based Microfluidic Screening Platforms–An Opinion

Developments in High Throughput Screening aim at maximizing the number of samples per time and reducing the cost per sample, e.g., by applying very small sample volumes. The ultimate technological step in miniaturization is moving from microtiter plate wells to droplets, and from batch-wise characterization to the continuous preparation and analysis of samples. A range of drop-based microfluidic screening platforms has emerged that benefit from drop-formation rates of thousands per second, perfect drop size uniformity, plug-flow and compartmentalization, and the possibility of continuously analyzing a train of drops. However, after many years of intensive research, only few commercial applications have been developed and substantial development in the field is still required to make them reliable and broadly applicable. Can academic research achieve this, given that most of the fundamental concepts have been described already, making it hard to publish a big story? Can start-up companies raise enough money to overcome the technical issues of drop-based screening platforms? This contribution addresses the question, focusing on how the different stakeholders in the field should interact so that disillusionment will not put a premature end to the development of drop-based screening technologies

Rheological Investigations on the Creaming of Depletion-Flocculated Emulsions

Preventing creaming or sedimentation by the addition of thickeners is an important industrial challenge. We study the effect of the addition of a "free" nonadsorbing polymer (xanthan gum) on the stability against creaming of sterically stabilized O/W emulsions. Therefore, we analyze our samples using microscopy and rheological measurements. At low xanthan concentrations, the emulsions cream. However, above a certain concentration a three-dimensional network of droplets is formed, which can prevent creaming. We attribute the formation of this structure to depletion attraction. The rheological behavior of an emulsion that is macroscopically stable should be elastic, while it should be viscous for a creaming emulsion. In order to distinguish between stable and unstable samples, we measure their relaxation time by mechanical rheology and find a good correlation to the visual observation. However, the measured relaxation times are much shorter than the time-scales, on which we observe creaming. We hypothesize that the measured relaxation time is related to the droplet-droplet interaction. This determines the frequency at which microscopic rearrangements occur, which weaken the network structure prior to creaming. Based on this interpretation, the relaxation time gives direct access to the microstructural processes involved in creaming. We therefore suggest using it as a predictive parameter of creaming stability

A comparison of neural mechanisms in mirror therapy and movement observation therapy

Objective: To compare lateralized cerebral activations elicited during self-initiated movement mirroring and observation of movements. Subjects: A total of 15 right-handed healthy subjects, age range 22-56 years. Methods: Functional imaging study comparing movement mirroring with movement observation, in both hands, in an otherwise identical setting. Imaging data were analysed using statistical parametric mapping software, with significance threshold set at p<0.01 (false discovery rate) and a minimum cluster size of 20 voxels. Results: Movement mirroring induced additional activation in primary and higher-order visual areas strictly contralateral to the limb seen by the subject. There was no significant difference of brain activity when comparing movement observation of somebody else's right hand with left hand. Conclusion: Lateralized cerebral activations are elicited by inversion of visual feedback (movement mirroring), but not by movement observation